Pressure accumulators of this kind, which are called membrane accumulators, are prior art. Such pressure accumulators may be used in hydraulic systems as shock absorbers or pulsation dampers to dampen pressure shocks in a hydraulic circuit. Moreover, they may also be used as an energy source for a pump-less emergency circuit, and are also suitable, for example, as hydraulic compression springs and the like.
When using such pressure accumulators with a process gas, such as air or preferably nitrogen, the disadvantage is that the diaphragm becomes permeable to the enclosed gas depending on the chemical composition of the elastomer and its service life. The nitrogen or the air first dissolve in the elastomer and subsequently diffuse into the environment through evaporation. Thus, the amount of gas present in the storage system diminishes, and the operational reliability declines rapidly. This diminishing and decline renders the storage system unserviceable beyond reuse such that it must be discarded.
To increase the permeation resistance of an elastic, largely gastight synthetic membrane, the prior art is known to provide a multilayered composition of the membrane, where a layer from a cross-linked polysiloxane is applied through scraping on, spraying on, pouring on or brushing on (cf. DE 42 31 927 C2).
In another solution known from the prior art (see DE 44 05 009 A1), first and second synthetic membranes are provided to create a multilayered membrane unit, in which the first synthetic membrane is made of an elastomer, and the second synthetic membrane is a polyester film.